Citan O2 sensor issues

My 2012 Mercedes Citan with a diesel engine is throwing codes related to the O2 sensor. The check engine light is on, and I'm seeing a drop in fuel efficiency. I suspect the catalytic converter is working overtime because of this. Has anyone else dealt with a dodgy O2 sensor on their Citan? I've checked the sensor itself, and it seems okay, but I'm wondering if it's a cable or plug connection that's causing the issue before I consider replacing the O2 sensor. Any thoughts?

4 comment(s)

I had something similar happen on my Citan. Check the wiring harness connected to the O2 sensor. Is it visibly damaged or corroded? I'm not a mechanic, but that was the culprit for me. What's the error code?

I'll check the wiring harness super closely tomorrow. When you say 'similar,' do you mean exactly the same symptoms – check engine light, fuel efficiency tanking, and O2 sensor code? Was it a pain to get to the wiring?

Yeah, pretty much the same. Light on, fuel consumption went up. I didn't mess with it myself, just took it to a workshop. They sorted it quickly. Might be worth doing the same, just to be safe.

Turns out you were spot on. I checked the wiring harness, and the plug connection was indeed corroded. I cleaned it up as best I could, but in the end, I took it to a local shop. They replaced the connector and did a diagnostic check. Total cost was 95€. Check engine light's gone, and the fuel efficiency seems to be back to normal. Fingers crossed it stays that way!

Join the discussion now: